INTESTINAL CAPILLARIES .I. PERMEABILITY TO PEROXIDASE AND FERRITIN
INTESTINAL CAPILLARIES .I. PERMEABILITY TO PEROXIDASE AND FERRITIN
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DOI：
10.1083/jcb.41.1.33
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发表时间：
1969-01-01
影响因子：
7.8
通讯作者：
PALADE, GE
中科院分区：
文献类型：
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作者：
CLEMENTI, F;PALADE, GE
辣根过氧化物酶（mol.直径X50 A）和铁蛋白（mol.直径10 A）分别用作小鼠肠粘膜毛细血管中小孔系统和大孔系统的探针分子。静脉注射后，通过将Graham-Karnovsky组织化学程序应用于固定的标本，及时跟踪过氧化物酶的分布。发现示踪剂迅速离开血浆，并在注射后1分钟到达毛细血管周围空间。在1分钟和1分30秒之间，过氧化物酶反应产物的梯度可以定期显示在毛细血管周围;它们的高点位于内皮细胞有孔部分的对面。这些梯度被超过1分30秒的均匀分布所取代。电镜下观察，缺血后3-4 min，毛细血管周围出现铁蛋白。注射。像过氧化物酶一样，它最初产生短暂的梯度，在内皮的有孔部分对面有高点。对于这两种示踪剂，没有证据表明通过细胞间连接的运动，质膜囊泡的运输效率低于通过窗孔流出。它的结论是，在肠粘膜的毛细血管，隔膜的内皮窗包含的小孔系统的结构等价物。大孔隙系统似乎仅限于一小部分的fenestral人口，其中可能包括无菌或缺乏菌的单位。毛细血管和肝血窦的大小孔之比分别为~ 1：30，000和1：340。肠毛细血管的可用数据较为有限。其小孔的直径由Mayerson等人估计为~ 220 A。(2)他们对宫颈毛细血管的小孔给出了相同的值。Grotte（1）也研究了后者，他计算出小孔的直径为70-90 A。由于Grotte对数据的处理更全面，我们将假设小肠毛细血管的小孔系统也具有相同的尺寸。
Horseradish peroxidase (mol. diam. X50 A) and ferritin (mol. diam. til10 A) were used as probe molecules for the small and large pore system, respectively, in blood capillaries of the intestinal mucosa of the mouse. Peroxidase distribution was followed in time, after intravenous injection, by applying the Graham-Karnovsky histochemical procedure to aldehyde-fixed specimens. The tracer was found to leave the plasma rapidly and to reach the pericapillary spaces 1 min post injection. Between 1 min and 1 min 30 sec, gradients of peroxidase reaction product could be demonstrated regularly around the capillaries; their highs were located opposite the fenestrated parts of the endothelium. These gradients were replaced by even distribution past 1 min 30 sec. Ferritin, followed directly by electron microscopy, appeared in the pericapillary spaces 3-4 min after i. v. injection. Like peroxidase, it initially produced transient gradients with highs opposite the fenestrated parts of the endothelium. For both tracers, there was no evidence of movement through intercellular junctions, and transport by plasmalemmal vesicles appeared less efficient than outflow through fenestrae. It is concluded that, in the blood capillaries of the inintestinal mucosa, the diaphragms of the endothelial fenestrae contain the structural equivalents of the small pore system. The large pore system seems to be restricted to a fraction of the fenestral population which presumably consists of diaphragm-free or diaphragm-deficient units. order mentioned, the ratio large to small pores being-1: 30,000 and 1: 340 in leg capillaries and liver sinusoids respectively. Data available for intestinal capillaries are more limited. The diameter of their small pores is estimated at-220 A by Mayerson et al.(2) who give the same value for the small pores of cervical capillaries. The latter have also been studied by Grotte (1) who has calculated a diameter of 70-90 A for the small pores. Since Grotte's treatment of the data is more comprehensive, we shall assume that the same dimensions obtain for the small pore system of intestinal capillaries.